What is the meaning of the linker error in QT IOS where the entry point (_main) is undefined?

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The linker error in QT iOS where the entry point (_main) is undefined occurs when the linker cannot find a function called "main" to start the program. This typically happens if the application is missing the required main function or if there are multiple main functions defined in the application. The error can also occur if the application is not compiled correctly or if there are missing libraries or dependencies that are required for the application to run.